Does the term "joint tenancy" apply to the issue of severance?

I note the use of the term "joint tenancy" is not conclusive of the issue of severance. In Landon v. Blaskovits (January 31, 1986) Vancouver, No. 84/871 (B.C.S.C.), a couple's matrimonial home was registered in their names as joint tenants. A purchase and sale agreement was entered into that only referred to the manner in which the parties held the property on the backing page, where it referred to the parties as joint tenants. A separation agreement was executed wherein the parties agreed to sell the property according to the terms of the purchase and sale agreement, and to equally divide the proceeds of sale with provision for a charge on a portion of the husband's share for the children's maintenance beyond his life. The separation agreement stated that the parties hold the property jointly. The separation agreement also included release of all claims against either of the parties' estates. The husband died, survived by a subsequent wife who claimed half the proceeds of sale from the property.